Glass-forming Region Research Articles

TeO2-Ga2O3-ZnO ternary tellurite glass doped with Tm3+ and Ho3+ for 2 µm fiber lasers

The glass-forming region of TeO2-Ga2O3-ZnO (TGZ) ternary tellurite glass was predicted via a thermodynamic method and then confirmed by a few experiments. Upon cooling the melts at a rate of ~20 K/s, the glass formation was observed within the range of 60–97 TeO2, 0–20 Ga2O3, and 0–40 ZnO (in mol%). For a better understanding of their fundamental physical, thermal and optical properties, the density, characteristic temperatures, Abbe number, linear and nonlinear refractive indices were comprehensively investigated. The possibility of TGZ glass host for 2 µm fiber lasers was studied through Tm3+ and Ho3+ doping and rare-earth sensitization. The results show such newly developed TGZ glass owns high thermal stability, low phonon energy and efficient 2 µm fluorescence, which enriches the tellurite glass system and may contribute to the research of high gain fiber lasers.

Amorphous Ga–Sb–Se thin films fabricated by co-sputtering

Ternary chalcogenides of a Ga–Sb–Se system are prospective materials for potential applications in the field of infrared optics. This Letter deals with the optical properties and photosensitivity of Ga–Sb–Se thin films deposited by co-sputtering, enabling us to fabricate amorphous thin films outside the glass-forming region. The optical bandgap range of 1.92–1.35 eV with corresponding refractive indices at 1.55 µm ranging from 2.47 to 3.33 can be reliably covered using G a 2 S e 3 and S b 2 S e 3 targets. Furthermore, the prolonged irradiation by the near-bandgap light under the pure argon atmosphere leads to the irreversible photo-bleaching effect in fabricated films. The magnitude of this effect decreases monotonically with an increasing antimony content.

Glass Formation in the AlCl3–(CH3)2SO–H2O System

Glass formation in the AlCl–(CH3)2SO–H2O system was detected for the first time, the boundaries of the glass formation region were determined, and glass AlCl3 · 2.9(CH3)2SO · 4.8H2O was synthesized. The IR spectra of glass-forming solutions within the boundaries of the glass formation region and the glass AlCl3 · 2.9(CH3)2SO · 4.8H2O were recorded. It was concluded that (CH3)2SO enters the first coordination sphere of the aluminum ion through the oxygen atom. The glass AlCl3 · 2.9(CH3)2SO · 4.8H2O was studied by calorimetry, and its glass transition temperature was determined to be Tg = –32.3°C.

Glass Formation in the PbO–GeO2 System

The glass-forming region in the PbO–GeO2 system is studied. To increase the glass-forming limit in this system, the tempering rate of the samples has to be increased using special methodological practices. The dependence of the temperature of the synthesis of lead germanate glass on the PbO content is obtained. It is shown that the corrosion of alumina crucibles proceeded during the synthesis of lead germanate glass. The dependence of the thickness of the corroded layer of the alumina crucible wall on the time of the synthesis of the glass of the 55PbO · 45GeO2 composition, mol % at 900°С is obtained. It is proved that the obtained glass is X-ray amorphous within the whole range of compositions in the PbO–GeO2 system.

The glass-forming region and 2.7 μm emission of Er3+-doped TeO2−Ta2O5−ZnO tellurite glass

An Er3+-doped TeO2 − Ta2O5 − ZnO (TTZ) tellurite glass has been investigated to explore its possible application in mid-infrared laser glass and fiber lasers. Glass-forming region of the ternary TTZ glass system was determined based on the thermodynamic calculation and experiments. Physical and optical properties of the TTZ glass were characterized in detail by using Raman, different scanning calorimetry, luminescence spectra, and fluorescence decay curves. An intense 2.7 μm emission was observed in Er3+-doped TTZ glasses upon the excitation of 980 nm laser diode (LD). The excellent thermal stability (△Tmax = 203 °C), low maximum phonon energy (~770 cm−1), high emission cross-section (0.82 × 10−20 cm2) and spectroscopic figure of merit (3.22 × 10−24 cm2s) indicate that the Er3+-doped TTZ glass could be a promising candidate for efficient ~ 3 μm fiber lasers and amplifiers.

Structural properties of alumina-doped lithium borovanadate glasses and glass-ceramics

This study elucidates the role of Al2O3 in the lithium borovanadate (LBV) system, Li2O-B2O3-V2O5, in improving the glass-forming region of LBV glass. This increased glass-forming tendency is likely due to formation of [AlO4]− units. 11B, 27Al, and 51V nuclear magnetic resonance measurements suggest an importance of V-O-Al linkages and distribution of Li for charge compensation of [AlO4]− and [BO4]− units. Intense 51V NMR signals and resolved hyperfine coupling patterns in the electron paramagnetic resonance (EPR) spectra indicate that the majority of vanadium is pentavalent (V5+) and minor amounts of paramagnetic vanadium (V4+) are present. The EPR interaction parameters suggest that the vanadyl-like environments can be described as tetragonally compressed distorted octahedra. Based on V-2p3/2 X-ray photoelectron spectroscopy, the V4+ concentration is estimated at <3%. These vanadate glasses are attractive for energy storage applications, as they have higher specific capacities than commercial lithium-ion battery cathodes.

Phase Formation in the Ternary System Nd2S3–Ga2S3–EuS

The ternary system Nd2S3–Ga2S3–EuS was studied by physicochemical analysis methods. The projection of the liquidus surface was constructed, and the boundaries of the glass formation region were found. It was determined that the ternary system consists of ten fields of primary crystallization of individual phases and the glass formation region. The thermolysis of the synthesized glasses was investigated, and their IR spectra were recorded. In the course of the thermolysis in an inert atmosphere, the glass (Ga2S3)0.70(Nd2S3)0.25(EuS)0.05 softens at 1010 K and then crystallizes at 1110 K. The mass loss proves that the exothermic events observed in the temperature range 1145–1225 K are related to stage-by-stage glass decomposition.

Glass-Forming Region in the Sm2S3–Ga2S3–EuS System

The boundaries of glass-forming regions in the Sm2S3–Ga2S3–EuS system have been located using simultaneous thermal analysis, X-ray diffraction, and X-ray microanalysis. We have studied IR spectra of glass with the composition (Ga2S3)0.80(Sm2S3)0.10(EuS)0.10 and its stability in an inert atmosphere. The glass has been shown to soften at 985 K (Tg), which is accompanied by an endothermic peak. It crystallizes at 1112 K (Tx). Exothermic peaks observed in the range 1203–1222 K suggest that this glass has a tendency to decompose in several steps. In the IR spectra of the glasses, the bands due to the M–S (M = Sm, Ga, Eu) bonds have higher intensity and are shifted to higher frequencies relative to those in the spectra of their crystalline constituent components, which is probably due to the increase in M–S bond covalence.

Design of composition, structure and optical properties of AsxSe100-x (15

We have demonstrated for the first time synthesis of amorphous As–Se films within a large compositional range (AsxSe100-x (15 < x < 96)), even beyond the As–Se glass formation region, by means of PECVD. The ability to design the film composition, structure and optical properties via changing the type of plasma discharge and energy input as well as precursor's temperature is revealed. The results obtained evidence the enlarged capability of the PECVD method developed in terms of production of As–Se-based planar structures.

Nd3+-doped antimony germanate glass for 1.06 μm fiber lasers

In this work, a multicomponent GeO2–Sb2O3–BaO (BSG) glass is explored to assess its potential for 1.06 μm fiber lasers. The glass-forming region of BSG system is predicted and determined experimentally based on a thermodynamic method. Benefitting from the incorporation of Sb2O3, this system possesses an exceptionally large glass-forming region, as well as high density and refractive index, wide infrared transmission range and low phonon energy. Furthermore, an efficient near-infrared emission at 1064 nm from Nd3+ has been realized in this oxide glass with relatively long measured lifetime (200.58 ± 1.24 μs) and large emission cross-section (3.015 ± 0.090 × 10−20 cm2), indicating that Nd3+-doped BSG glass is a promising candidate for laser application in 1.06 μm region.

Ionic conductivity behavior by activated hopping conductivity (AHC) of barium aluminoborosilicate glass–ceramic system designed for SOFC sealing

Non-conducting BaO-B2O3-Al2O3-SiO2 parent glasses designed for solid oxide fuel cell (SOFC) sealing applications were prepared using the melt-quenching technique. The glass formation region was determined according to phase equilibrium relations and was found to be in the composition range 70BaO-(x)Al2O3-(10−x)B2O3-20SiO2 where 3.0 < x < 6.0 wt%. The conductivity values obtained conductivity ranged from 10−5 to 10−10 S/cm at temperatures between 600 and 850 °C. The batch compositions presented a threshold of dc conductivity near 70BaO wt% with a quasi linear behavior with the decrease of the BaO content. Different values of conduction activation energy were observed at temperatures above the glass transition temperature (Tg) (up to 700 °C), which were attributed to the thermal bond-breaking of non-bridging oxygen (NBO) defects. The experimental results of the electrochemical characterization by impedance spectroscopy of glass–ceramic interfaces with yttria-stabilized zirconia (YSZ) acting as solid ionic conductor electrolyte are presented and discussed.

Nd3+-doped TeO2–MoO3–ZnO tellurite glass for a diode-pump 1.06 μm laser

Nd3+-doped TeO2–MoO3–ZnO (TMZ) tellurite glass with excellent glass-forming ability and optical property is explored for laser material applications. The glass-forming region is predicted via the “thermodynamic method” and then confirmed by some few sets of experiment. The fundamental characteristics of the TMZ glass such as glass structure, optical and spectroscopic properties are also investigated in detail by Raman, absorption, emission spectra and fluorescence decay curves. Interestingly, the vitrification, thermal and optical property of the present glass is significantly improved with the addition of MoO3. Furthermore, the TMZ glass has a higher emission cross section (3.12 × 10−20 cm2) and spectroscopic figure of merit (6.01 × 10−24 s·cm2) for the Nd3+: 4F3/2 → 4I11/2 transition. All results indicate the potential applications of the TMZ glass in laser materials.

Thermochemical properties and glass forming tendency modeling for the ternary Ge–Mn–Gd melts

Information on the thermochemical properties may be useful for predicting of the concentration regions of easy glass formation in multicomponent alloys. In present investigation the integral enthalpies of mixing for the Ge–Mn–Gd melts were determined for the entire concentration interval at 1830 K using the Redlich-Kister-Muggianu method. GFT values for binary and ternary alloys of this system were calculated. Size mismatch entropy was estimated within the frameworks of hard spheres model. On the basis of performed calculations the concentration regions in which the melts of the Ge–Mn–Gd system can demonstrate considerable tendency to easy glass formation were suggested.

Tl2S-GeS-GeS2 system: Glass formation, macroscopic properties, and charge transport

A relevant approach was found to study the glass-forming region, macroscopic properties and electrical conductivity changes in the Tl2S-GeS-GeS2 system by analysing two composition glass lines (Tl2S)x(GeS2)100-x (0 ≤ x ≤ 50) and (Tl2S)10(GeS)x(GeS2)90-x (0 ≤ x ≤ 90) together with three thallium containing crystalline compounds Tl4Ge4S10, Tl4Ge2S6 and Tl4GeS4. The crystallisation ability variation in the binary Tl2S-GeS2 system can be explained comparing the structural characteristics of glasses and closest crystalline compounds. The room temperature dc conductivity increases by 7 orders of magnitude with increasing thallium concentration and reaches the value of 10−8 S cm−1 for (Tl2S)50(GeS2)50 sample. Combined with the previously obtained conductivity and thallium diffusion parameters for (Tl2S)x(GeS)60(GeS2)40-x and (Tl2S)x(GeS)50-x/2(GeS2)50-x/2 composition lines as well as with conductivity characteristics for the crystalline analogues, the ionic and electronic conductivities in the (Tl2S)x(GeS2)100-x glasses were estimated separately. The Tl-poor glasses (x ≤ 0.25) are essentially semiconductors, while the Tl-rich vitreous alloys appear to be ionic conductors. The conductivity parameters for (Tl2S)10(GeS)x(GeS2)90-x glasses change non-monotonically with GeS concentration passing by the conductivity minimum for 60% mol. GeS. The same behaviour was observed for thallium free (GeS)x(GeS2)100-x matrix, showing the influence of the GeS/GeS2 ratio on the properties of the thallium-poor semiconducting glasses.

Atomistic simulation study of favored compositions of Ni-Nb-Al metallic glasses

This study investigates the formation process of Ni-Nb-Al metallic glasses. To this end, a long-range n -body potential was constructed for the Ni-Nb-Al ternary metal system, and applied to atomistic simulations. The simulations not only showed the physical origins of the amorphous phase formation, but also quantitatively predicted a hexagonal compositional region that energetically favors the glass formation. The energy difference between the solid solution and metallic glass, which generates the amorphization driving force (ADF), was suggested to indicate the glass-formation ability (GFA) of each alloy. Based on the computed ADFs, the Ni55Nb25Al20 alloy exhibited the highest GFA among the Ni-Nb-Al members, implying that the glass formed by this amorphous alloy is more thermodynamically stable than other alloys in the system. In a Voronoi tessellation analysis, the knee point of the coordination-number distribution curve corresponded to the glass-formation region of the Ni-Nb-Al system.

Glass formation and structural studies of glasses in the TeO2 – ZnO – Bi2O3 – Nb2O5 system

In this study we determined the glass formation region in the TeO2 - ZnO - Bi2O3 - Nb2O5 system. The investigation covers TeO2 - based glasses containing ZnO (from 10 to 40 mol%), Bi2O3 (6–10 mol%) and Nb2O5 (6–10 mol%). The glasses obtained were transparent and yellow in colour. The thermal stability of the samples determined by DTA was found to be about 100 °C. Some physical characteristics (density, molar volume, oxygen molar volume and oxygen packing density) were estimated as well. The analysis of IR spectra showed that the network of glasses consists mainly of TeO4 (tbp) units, while Raman spectroscopy revealed the existence of TeO4 (tbp), TeO3+1 and TeO3 (tp) units. The UV–Vis spectroscopy established a red shifting of the cut-off depending on composition and the glass rich in TeO2 exhibited cut-off at about 388 nm while that with low TeO2 content was 378 nm.

Prediction of glass forming regions in mixed-anion phosphate glasses

Fluoro-sulfo-phosphate glasses with rich ligand situations and excellent thermal stability are promising host materials for optically active species, injection moulding and low-temperature sealing, which have received a significant amount of interest in recent years. Herein, the glass-forming regions of such inverted glass systems are predicted via the thermodynamic method. Based on this, the actual glass formation areas are further determined by the experiments. The liquidus and eutectic points of the binary systems are calculated and the deviations in composition between the calculated results and available phase diagrams are determined with a small deviation (<6 mol%). Meanwhile, the glass-forming regions are derived quantitatively, which are relatively in agreement with the experimental results. These results demonstrate that it is practical to predict the formation regions of fluoro-sulfo-phosphate glass systems based on thermodynamic calculation, providing an effective and predictive method for the development of new glass systems.

Quantitative prediction of the structure and properties of Li2O–Ta2O5–SiO2 glasses via phase diagram approach

AbstractTantalum silicate glasses serve as laser host materials to take advantage of their high refractive index and the ability to tailor their physical properties in the design of high‐performance photonic and photoelectric components. However, successful attainment of feature control in tantalum‐doped materials remains a longstanding problem due to the limited understanding of local structure around the tantalum ions, a problem that lies at the heart of predicting the micro‐ and macroscopic properties of these glasses. Herein, we present a novel approach for predicting the local structural environments in tantalum silicate glass based on a phase diagram approach. The phase relations and glass formation region of Li2O–Ta2O5–SiO2 ternary systems are explored to calculate the structure and additive physical properties of lithium tantalum silicate glasses. These measured and calculated results are in good quantitative agreement, indicating that the phase diagram approach can be applied broadly to Li2O–Ta2O5–SiO2 ternary glass systems. Using the phase diagram approach, the local structure of tantalum can be directly obtained. Each Ta atom is surrounded by six atoms, and its polyhedron, the TaO6 octahedron, bonds through oxygen to Li and Ta. As a network modifier, Ta5+ depolymerizes the silicate glass structure by modulating the local structure of lithium atoms in Li2O–Ta2O5–SiO2 ternary glass system. The compositional dependence of structure in lithium tantalum silicate glasses is quantitatively determined based on the structure of the nearest neighbor congruent compound through the lever rule. These findings offer a precise prediction of tantalum silicate glass properties with quantitative control over local structural environment of the disordered materials.

Glass Formation in the Ternary System La2O3–As2S3–Er2O3

The boundaries of the glass formation region in the ternary system La2O3–As2S3–Er2O3 were found. Transparent glass of composition (La2O3)0.03(As2S3)0.90(Er2O3)0.07 was studied by X-ray photoelectron and Raman spectroscopy. The intensities of the bands characterizing As–S, La–O, and Er–O bonds increased, and these bands were shifted toward higher energies. This was due to an increase in the covalence of these bonds and probably due to the formation of new bonds in the glasses. Samples in the glass formation region are resistant at 300 K to air, water, and organic solvents.

GLASS FORMATION IN TERNARY SYSTEM La2O3–As2S3–Pr6O11

Boundaries of glass formation in ternary system La2O3-As2S3-Pr6O11 were studied using methods of physical-chemical analysis (DTA, DTG, X-ray analysis, MSA). It was established that in glass formation region the range of concentration covers from As2S3-La2O3 15 mol%, but from As2S3-Pr6O11 it is 13 mol%. To our opinion the decrease in glass formation region of Pr6O11 comparing to La2O3 is related to crystalline structure of oxide, i.e. to the change in coordination number of lanthanides. Because properties of compounds of lanthanide are more sensitive to the change in coordination numbers relative to radii of ion. In the system the region of transparent glass formation is limited with the region of non-transparent one. The reason of non-transparency of a glass is the formation of primary centers of crystallization, which was confirmed by the results of X-ray analysis and SEM. Raman spectra of transparent glass containing(La2O3)0.07(As2S3)0.90(Pr6O11)0.03 were studied. Intensity of bands which characterize the bonds of As–S, La–O, Pr–O in Raman spectrum and shift of energy of waves in the big party are related to the strengthening of bonds and probably, appearance of new bonds in glasses. When heating glasses of the composition (La2O3)0.07(As2S3)0.90(Pr6O11)0.03 in inert atmosphere (He) at 224,61 °С it softens which is followed by endoeffects. Observed exoeffect at 315,80 °С satisfies crystallization of glass, but at 380,80 °С thermal decomposition begins. Samples in the region of glass formation are stable at 300 K to air, water and organic solvents. When heated, glasses are dissolved in chromic mixture. They decompose in mineral acids and alkalies.Forcitation:Bakhtiyarly I.B., Fatullayeva G.M., Kerimli O.Sh. Glass formation in ternary system La2O3–As2S3–Pr6O11. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 4-5. P. 43-48